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If first excitation potential of a hydrogen-like atom is V eV, then the ionization energy of this atom will be :
First excitation energy
Linear momenta of a proton and an electron are equal. Relative to an electron
If pe = pp,
The wavelength of a photon and the de-Broglie wavelength of an electron and uranium atom are identical. Which one of them will have highest kinetic energy
for photon & electron
The correct answer is: Photon
The energy E and momentum p of photon is given by E = hv and p = h/λ, the velocity of photon will be :
E = hc/λ put c = v
and p = h/λ
E = pv
⇒ v = E/p
The correct answer is: E/p
In the figure six lines of emission spectrum are shown. Which of them will be absent in the absorption spectrum.
The photon’s with energies equal to that required for upward transition A → X, A → B and A → C would be absorbed, these photons shall be absent from absorption spectrum.
The correct answer is: 1, 2, 3
A charge particle q0 of mass m0 is projected along the y-axis at t = 0 from origin with a velocity V0. If uniform electric field E0 also exists along the x-axis, then the time at which de-Broglie wavelength of the particle becomes half of the initial value is :
Initial debrogle wavelength of the charge particle
After any time t,
Suppose after time t, λ becomes half of the initial value i.e.
What voltage must be applied to an electron microscope to produce electrons of
The correct answer is: 150 Volt
In X-rays production an electron accelerated with voltage V strikes a metal target. For which of the following voltages X-rays of minimum wavelength will be produced :
λ will be minimum for maximum accelerated voltage
The correct answer is: 40 kV
In the photoelectric, if we use a monochromatic light, the I-V curve is as shown. If work function of the metal is 2eV, estimate the power of light used. (Assume efficiency of photo emission = 10–3 % i.e. number of photoelectrons emitted are 10–3 % of number of photons incident on metal.)
The energy of incident photons is given by
(Vs is stopping potential and is work function)
Saturation current = (η is photo emission efficiency)
∴ P = 7mW
The correct answer is: 7mW
In Davisson-Germer experiment the relation between the angle of diffraction θ and the grazing angle φ is.